Circuit-closer.



H. C. THOMSON.

CIRCUIT CLOSER.

APPLICATION FILED MAR. s, 1909.

959,435, Patented May 24,1910.

UNITED STATES PATENT OFFICE.

HENRY C. THOMSON, BOSTON, MASSACHUSETTS, ASSIGNOR TO ELECTRIC -I'OO DS MANUFACTURING COMPANY, A CORPORATION OF MAINE.

CIRCUIT-CLOSER.

sional changes in said element, as a resultof the application of force to such element; said element however embodying a resiliency adapted to restore the same to substantially its originalform and dimensions when such force is removed. Preferably said distortieble member isembodied in the'formof an annular member consisting of a length of helically coiled spring wire bent into a ring, with its free ends hooked together, as shown in Fig. 3,- or otherwise connected in any suitable manner.

The distortible member is positioned on the surface of the base block by the plunger 13, which preferably passes through the central opening in said distort-ible member. The length of the helical spring from which the distortible member is formed is preferably such that the same is closely contracted around the plunger, and adapted to exert a force upon the tapering surface of the plunger suflicient to force the same to its extreme upper posltion as shownin Fig. 2. In such upper position the outer diameter of the distortlble member, 17, and the diameter of thecircular arc in which the contact strips 9- are curved are so proportioned that said distortible member is out of contact, at least with one,-and preferablywith both, of said curved strips. When said button is pushed the tapering portion of the plunger 13 is caused to enter more deeply within the inner opening of the distortible annular member, the increasing diameter of the plunger brought in contact with said annular member as a result of such movement causing the distortion of said annular member from its original dimensions, and producing a diametral expansion of-the'same which will eventually bring the outlying points of its various convolutions into contact with the curved contact strips 9 lying peripherally adjacent thereto. It is evident that when each contact strip is thus in electrical connection with the distortiblemember, both will be electrically connected with each other through said distortible member, thus closing the circuit.

It maybe here pointed out that the distortible member. should preferably be: sufficiently resilient so that that coil or other point of contact on the surface of said distortible member which first comes into .con tact with a contact strip will yield, as an increasing pressure is applied to the plunger, until a sufiicient number of the coils embodied in said distortible member or other points in said of contact on its surface are in contact with the contact strips to insure a satisfactory electrical connection between the distortible member and each of the contact strips. It may further be noted thespreading of the convolutions of the distortible member incident to the diametral expansion thereof tends "to produce a slight rubbing between the said convolutions and the contact strips which maintains the contacts always clean and bright, insuring perfect electrical engagement. F urthermoretdie movement of the plunger 13 relative to the'annular distortible member is apt to cause a slight rotation of the several convolutions about the axis of the annular member which further aids in securing the rubbing contact between said distortible member and the contact strips.

In case the distortible member becomes so -'fouled by dirt as to seriously impair the Working of the circuit closer it is a simple and inexpensive matter to replacethe distortible member by a new one.

In the type of circuit closer hereinabove described it is evident that the circuit will remain closed only so long as pressure is continuously applied to the button, 12. In case it is desired to embody my invention in a circuit closer or switch adapted to remain automatically closed for an indefinite period the modification illustrated in Fig. 4 may be employed. Said Fig. 4 showsqnerely the operative portion of such a switch in its closed position, the outer casing, similar to that shown in Figs. 1 and 2 belng omitted. As above described in connection with said Figs. 1 and 2 the operative portions of the switch comprise the distortible member 21 resting on one end of the base block 22 and centrally positioned thereon with respect to the contact strips 23 mounted on said base block 22 bythe plunger 24.. As before, said contact strips are connected with the conductor bars 25 on which are formed the binding posts for connecting said switch into the circuit to be controlled thereby. The distortible member 21 preferably consists of a ring of coiled spring made up substantially as previously described and contracted upon the plun er, which is longitudinally movable knob 26 being preferably provided for the purpose of manually moving said plunger when it is desired to operate said switch.

The plunger employed in the switch of Fig.

4 embodies the tapering portion 27 'which ase block, within fixed limits, a

' member great enough to permit the breaking of the contact between the said distortible member and the contact strips. In-order to tortible member from the groove, 29,.asthe plunger is pulled outwardly from the base block, a cover, 30, is provided which is secured to the base block at its lower edge, and embodies an upper surface projecting over said'distortible member, adapted to prevent the material dislodgment of the said 'member as the plunger is moved.

Another embodiment of my invention is presented in Figs. 5, 6 and 7' showing the same-as applied in a push-button of ordinary type, andembodying a modified form of distortible member and showing a modification in the manner of causing the. diametral expansion of the same. As shown in said figures the body, 31, of said push-button has a supporting shell, 32, secured in the central opening of the body,-and having its lower edge turned over as shown, so as to support the operative portion of said button. The operative portion of said button comprises the base, 33, preferably of insulating material, having the plunger, 34, centrally mounted in the same by means of the guide shank, 35,- which is longitudinally slidable, in said base, and having its upper portion formed into a button as shown for manipulating said plunger. Said button portion of the plunger, 34, preferably has a at lower surface as shown, which normally rests upon the upper surface of a distort-ible member, 36, whlch is preferably annular or ring shaped in form, and is adapted .to closely encircle the guide shank, 35. Said annular member preferably is made up of resilient. wire. of high conductivity interwoven as more clearly shown in Fig. 7 so asto form an annular ring-whose body is sub.

-stantially circular in cross section; said ring also being constructed so as to embody a capacity for diam'etral expansion as it'is compressed between two opposing surfaces. The lower surface of said annulardistortible member rests upon" the base, 33. Peripherally adjacent to, but normally out of con: tact with the said distortible member are the contact strips, 37, se'curedto the base, 33, by the screws, 38, and electrically connected to the terminals of the circuit which the push-button is designed to control. Said strips are preferably curved so as to closely surround the said distortible member for slightly less than one-half of its circumference. If now the button be pushed so as to depress the plunger, the annular distortible member will be compressed between the lower surface of the button and the base block, producing a flattening of the same as shown in Fig. 6, and causing the diametral enlargement of the same. In consequence the said distortible member will be brought into peripheral contact with both of said contact strips, 37, as is shown in Fig. 6 establishing electrical connection between thev same and closing the circuit. On releasing the pressure on the'button the resiliency of the distortible member will cause it to-resume 'its original cross sectional area, resulting in a diametral shrinkage of the same which destroys the peripheral contact of the same with the contact strips, and thus opens the circuit.

Having described: my invention I claim as new and desire to secure by Letters Patent? 1. An electric circuitcloser comprising essentially a base block, electrically insulated contact members mounted upon said base block, andtformingthe terminals of an electric circuit, a distortible conducting member positioned adjacent said contact members, a plunger longitudinally movable with respect to the said base block, said plunger being adapted to secure said distortible member in its assembled relation inthe circuit closer, and to position the same with reference tosaid contact members so that in' its undistorted condition it is inoperative as. an electrical connection between the same, and

means rendered operative by the movement of the plunger to distort said distortible member and thereby ,to render it effective as an electrical connection between said contact members.

2. An electric circuit closer comprising essentially a base block, electrically insu lated contact members mounted upon said base block, and forming the terminals of an electric circuit, a distortible conducting member positioned adjacent said contact members, a plunger longitudinally movable with respect to the said base block, said plunger being adapted to secure said dis-. tortible member in its assembled relation in thecircuit closer and to position thesame with reference to said contactmembers so thatin its undistorted condition it is inoperative as an electrical connection between the same,,said plunger and base block having coo crating surfaces which become effective, as t e plunger is moved longitudinally with respect to the base' block, to cause a distortion of the distortible member whereby the same is rendered operative to electrically connect said contact members.

3. An electric circuit closer comprising essentially a base block, electrically insulated t a &

contact members mounted on said base block and forming the terminals of an electric circuit, a plunger longitudinally movable with respect to the said base block, said plunger having a tapered portion, a resilient diametrically expansible conducting ring no'rma'lly contracted about the said plunger adjacent the smaller end of the tapered por- 4. An electric circuit closer comprising es sentially a base-block, electrically insulated contact members mounted on said baseblock and forming the terminals of an electric circuit, a plunger longitudinally movable with respect to said base-block, and having a tapering portion, a resilient diametrically expansible conducting ring normally contracted about the plunger adjacent the smaller end of the tapering portion of the same, said ring in such contracted, condition being positioned by said plunger so as to lie peripherally adjacent to, but out of contact with said contact members, the longitudinal movement of said plunger being adapted to cause a diametral expansion in said ring whereby it is,caused to simultaneously contact with both said contact members.

5. An electric circuit closer comprising essentially a base-block, electrically insulated contact members mounted at one end of the base-block and forming the terminals of an electric circuit, a resilient diametrically expansible conducting ring supported by the base-block, and lying between but normally out of contact with said contact members, and a plunger longitudinally movable with relation to said base-block, and embodying a tapering portion adapted to be entered within the central opening in said ring as said.

plunger is moved toward said ring, and 7 iency normally tending to keep the same in a contracted conditiom'contact members, forming the terminals of an electric circuit, mounted on said base-block so as to be peripherally adjacent but out of contact with said ring in its contracted condition, and a plunger longitudinally movable in said baseblock, said plunger having a tapering portion whose smaller end is adapted to pass through the central openin of said ring when in its contracted condition and thereby maintain the same-in a position wherein it is out of contact with said contactv members, said tapering portion beingadapted to be forced into said central, opening as the plunger is caused to move, thereby effecting a diametral expansion of said ring sufiicient to bring the same into simultaneous contact with said contact members.

In testimony whereof I afiix my signature in presence of two witnesses.

HENRY C. THOMSON,

Witnesses:

NATHAN B. DAY, CHAS. F. RANnAim. 

